Elucidation of the ultrafast isomerization mechanism of rhodopsin, a photoreceptor protein present in vertebrates, has been one of the central focuses of vision as well as ultrafast spectroscopy. Upon absorption of light by 11-cis retinal, the cofactor in rhodopsin, an ultrafast isomerization reaction takes place with high efficiency, 67%, to form all-trans retinal. In this project, we plan to study some rhodopsin analogues which contain 11-cis-locked-ring retinals with five-, seven-, and eight-membered rings. They have been shown to reconstitute with opsin and possess similar ground state absorption spectra as the native system. Previous work by Nakanishi and coworkers has shown that the retinal analogues undergo isomerization to a limited extent depending upon the ring size. We plan to investigate the transient anisotropy signals from these systems in the hope that they will help us better understand the anisotropy response we have previously observed in native rhodopsi n. These systems should be much easier to work with since they do not undergo permanent photobleaching like the native system.